Does Retinol Prevent Colorectal Cancer Metastasis?

描述（申请人提供）：远处结直肠癌转移患者的5年生存率为10%。类维生素a已被证明可以减少癌细胞的生长，但其在转移中的作用却很少受到关注。我们的长期目标是了解膳食维生素A（视黄醇）如何抑制结直肠癌的进展。我们已经证明视黄醇可以降低体外抗维甲酸结肠癌细胞的侵袭，降低Akt磷酸化、β -连环蛋白和基质金属蛋白酶7 （MMP7）的水平。我们的目的是：(1)确定维生素A是否抑制体内转移；(2)阐明视黄醇抑制转移的信号通路。目的1将用裸鼠脾内注射人结肠癌细胞来诱导肝转移。20只老鼠将摄入足够的维生素a作为对照饮食。额外的小鼠将食用维生素a含量增加至200,000 ILJ/kg的日粮。肝转移的数量和大小将被确定。我们预计补充维生素A可以减少转移瘤的数量和大小。目的2将确定视黄醇减少侵袭的信号通路。视黄醇降低Akt磷酸化，组成活性Akt阻断视黄醇对侵袭的作用。Akt磷酸化降低导致GSKSbeta活性增加。GSKSbeta靶向蛋白体降解的-连环蛋白。过量的核β -连环蛋白增加了有利于转移的基因的表达（例如MMP7）。Akt的组成活性和显性阴性形式，以及过表达或siRNA技术改变GSKSbeta和β - catenin水平将决定每种蛋白对细胞侵袭、生长和MMP7 mRNA水平的影响。为了将Aim 1和Aim 2联系起来，将在Aim 1中使用的小鼠切除的肿瘤中测量每种蛋白质。我们预计视黄醇会在体外和体内降低Akt和GSKSbeta磷酸化以及β -连环蛋白和MMP7水平。此应用程序的目标与NCI和pa# 04-108的目标一致。具体来说，我们将研究营养素维生素a预防结肠癌转移的能力，并确定视黄醇用于减少转移的信号通路。结肠癌转移的存活率很低。在实验室实验中，维生素A降低了结肠癌细胞移动和侵入组织的能力。该应用程序将确定维生素A是否可以减少小鼠的转移以及受维生素A影响的调节转移的蛋白质。

DESCRIPTION (provided by applicant): The five-year survival rate for patients with distant colorectal cancer metastasis is 10%. Retinoids have been shown to decrease cancer cell growth, but their role in metastasis has received little attention. Our long-term objective is to understand how dietary vitamin A (retinol) inhibits colorectal cancer progression. We have shown that retinol decreases retinoic acid-resistant colon cancer cell invasion, and Akt phosphorylation, beta-catenin, and matrixmetalloproteinase 7 (MMP7) levels in vitro. Our aims are (1) to determine if vitamin A inhibits metastasis in vivo and (2) to elucidate the signaling pathway retinol uses to inhibit invasion. Aim 1 will use nude mice injected intrasplenically with human colon cancer cells to induce liver metastases. Twenty mice will consume a vitamin A sufficient control diet. Additional mice will consume a diets containing increasing amounts of vitamin A up to 200,000 ILJ/kg diet. Hepatic metastases number and size will be determined. We expect vitamin A supplementation to decrease metastases number and size. Aim 2 will determine the signaling pathway by which retinol decreases invasion. Retinol decreases Akt phosphorylation and constitutively active Akt blocks the effect of retinol on invasion. Decreased Akt phosphorylation results in increased GSKSbeta activity. GSKSbeta targets beta-catenin for proteosomal degradation. Excess nuclear beta-catenin increases the expression of genes favoring metastasis (e.g. MMP7). Constitutively active and dominant negative forms of Akt, and overexpression or siRNA technology to alter GSKSbeta and beta- catenin levels will determine the effect of each protein on cell invasion, growth, and MMP7 mRNA levels. To link Aim 1 and 2 each protein will be measured in tumors excised from the mice used in Aim 1. We expect that retinol will decrease Akt and GSKSbeta phosphorylation as well as beta-catenin, and MMP7 levels in vitro and in vivo. The goals of this application are consistent with those of the NCI and PA# 04-108. Specifically, we will examine the ability of a nutrient, vitamin A, to prevent colon cancer metastasis and determine the signaling pathway retinol uses to decrease metastasis. The survival rate from colon cancer metastasis is very low. Vitamin A decreases the ability of colon cancer cells to move and invade tissues in laboratory experiments. This application will determine if vitamin A can decrease metastasis in mice and the proteins affected by vitamin A that regulate metastasis.